DESCRIPTION: Developing strategies for recognizing and treating children with sleep Disordered Breathing (SDB) is not possible in the absence of essential epidemiological data that addresses the distribution of measures of SDB in pediatric populations. The potential public health importance of this is underscored by preliminary data that suggest that suggest that risk of SDB is increased in susceptible populations, in particular in Africa Americans and in children born prematurely. The goals of this study are to collect fundamental data regarding the distribution of measures of SDB in a pediatric population, prevalence of clinically significant SDB in children, risk factors, and associated co-morbidity. In this cohort study with a nested case control arm, the investigators will exploit access to a well-characterized cohort of 8 to 10 years olds (50 percent born prematurely) who have participated in longitudinal studies of behavior and cognition. SDB will be evaluated in 850 children with in-home state-of-the-art respiratory monitoring techniques. A broad array of risk factors will be evaluated: sociodemographic characteristics; anthropometry; upper and lower airway size and function (questionnaire, spirometry, and reflectometry); perinatal exposures (from neonatal records); family history; and home environment (passive smoking; sleep patterns, maternal-child stress indices). Behavior, cognitive skills, attention, and health-related quality of life will be assessed with standardized instruments to assess co-morbidities (potential SDB outcomes). Analysis of the longitudinal data will provide cognitive-developmental trajectories that will be evaluated in relationship to SDB. The case-control arm will confirm and extend the findings in the in-home assessments with comprehensive laboratory polysomnographby, cephalometry, and objective measures of sleepiness (Multiple Sleep Latency Tests) in three groups of children: definite SDB by home assessment; equivocal SDB; and no SDB. Collection of comprehensive polysomnographic data will help identify which measures best discriminate symptomatic (e.g., snoring, sleepy) from asymptomatic children. Extensive risk factor and outcome measurements should provide data that will improve strategies for identifying and intervening in high-risk children. Follow-up of a cohort with a large number of preterm children also affords an excellent opportunity to study SDB co- morbidities in a group at high risk for developmental delays (who may be susceptible to additive adverse effects of SDB) and to explore new hypotheses regarding the role of developmental factors in SDB.